Process of making laminated metal



July 26, 1932v s. L LL 1,868,749

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Patented July 26, 1932 UNITED -s'rivras- -PATE'N'n OFFICE STEPHEN L.INGERSOLL, OF CHICAGO, ILLINOIS, ASSIGNOR TO INGERSOLL STEEL& iDISG CO.,OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS PROCESS OF MAKINGLAMINATED METAL Application filed December 21, 1931. Serial No. 582,375.

This invention relates to a method of making composite metal articlesand particularly toa method of-making laminated steel sheets, strips,bars or slabs.

In the methods previously in use, in forming composite metal articles orslabs, it has been customary to unite dissimilar metals by variouswelding processes. Such methods have not been entirely satisfactorybecause numerous precautions must be taken in endeavoring to obtain asatisfactory bond between the metals. Also when one of the metalsurfaces in a finished product is to be polished, the temperaturetowhich the metal must be heatedin effecting the weld, particularly in theatmosphere of the furnace, has a marked eect on the surface of themetal, causing pitting, scaling and other defects that require aconsiderable amount of polishing and/or grinding to eliminate. j

It has also been customary to form composite metal articles by castingand rolling but such processes as heretofore practiced have had thedisadvantage that no protection for thgysurfaces to be polished or to beexposed 1n use is provided during the forming According to thisinvention, two metals,

slabs or the like, each of which may have a polished, smoothed, cleaned,or otherwise prepared surface'are placed together with such preparedsurfaces in juxtaposed relation but separated by a medium that preventspermanent or substantial welding of the said surfaces in the subsequentoperations. The

adjacent edges surrounding thecommon surfaces of the composite slab arethen welded and the composite slab is next placed in a mold and anothermetal poured around it. After removal from the mold, the ingot issubjected to a hot rolling operation which completely welds the castmetal to the metal slabs but does not weld the prepared surfacestogether due to the presence of the separating medium. The rollingoperation naturally .enlarges the area of the prepared surfaces.

The rolled form is then separated along the prepared surfaces to formtwo composite sheets each of which; presents a smooth surface. By thismethod the disadvantages attending previously used processes areentirely overcome.

Itis therefore an obj ect'of this invention to provide an expedientmethod of forming compos-ite metal sheets wherein protection is sheetsby forming composite slabs in multiple rolling the composite slabs to amultiple o the nal thickness desired and separating the rolled form intoindividual composite sheets each of the desired thickness.

It is also a particular object of this invention to provide a method ofcoating and rolling composite slabs to obtain a composite metal sheethaving large, smooth, even and vscale free surfaces without thenecessity of a large number of rolling operations.

It is a still further particular object of this invention torprovideamethod for protecting a prepared surface during forging or rollingoperations on the metal.

These and vother objects of this invention will be apparent from thefollowing description and appended claims.

This invention (in a preferred form) is illustrated in the accompanyingdrawing and Figure 1 is a plan view of two juxtaposed A slabs of metalhaving a separating composition between them.

Fi ure 2' 's a vlew similar to Figure 1 showing the adjacent edges ofthe'metal slabs welded. v

`Figure 3A is a plan view of a mold used to carrjr out my invention;Figure 4 1s a sectional view of the mold of ure 3 taken approximately onthe line sg I -IV of Figure 3 after pouring.

Figure 5 is a plan view of a composite metal 10 ingot removed from themold.

Figure 6 shows a form rolled from the in ot ofFigure 5.

igure 7 shows the rolled form of Figure 6 with its ends removed.

Figure 8 shows a single sheet of composite metal.

Figure 9 illustrates a multiple molding ar and allowed to cool. Theingot thus formed is removed from the mold, usually reheated and hotrolled into convenient sheet form. After this, the margins are clippedoi' back to the separated surfaces. The sheet tends to break apart alongthe line of theseparatingV composition to form two sheets of metal, eachhaving its prepared surface unalfected by outside agents during therolling operation or because of the heat incident thereto.

While the above illustrates the general principles of this invention, myinvention is particularly applicable for forming sheets p of compositemetal particularly where one of the metals is stainless steel such as18% chromium-8%nickel steel or 16 to 18% chromium, 0% nickel steel,rustless iron, or the like, and for a fuller understanding of thisinvention the yfollowing detailed description of the preferredembodiment of my invention is given. Y

As shown in Figure 1, two slabs 1 of stainless steel are used. Onesurface 2 of each is cleaned and prepared, as for instance, by picklingand polishing. The prepared surfaces 2 are then coated with a separatingcomposition 3, which may suitably be composed of red lead and sodiumsilicate (water glass) The proportions by volume of this mixturepreferably are as follows:

200 parts sodium silicate.

300 parts of red lead.

parts of water.

While this composition has been found tor position should fully coverthe juxtaposed surfaces, leaving no uncoated spaces.

The slabs 1, coated as above, are placed together with theiry preparedor. polished coated surfaces 2 in juxtaposed relation. The adjacentedges Vofl the slab 1 are welded, as shown at Il, to hold tbe slabs inplace and to prevent the liquid metal which is poured around the slabs,or other foreign material, from flowing between such surfaces, or togive protection against atmosphere and fur# nace gases when the slabsare rolled without casting molten metal around them.

The welded slabs 1 are then placed in a mold 5. The mold 5 may be of anysuitable material and is of suflicient size so that the metal to bepoured kwill entirelyY surround j the slabs 1. 'lhe mold is providedwith a number of bridges 6, preferably made of metal of the samecomposition as that being poured, which lie across the bottom of themold and which support the slabs in spaced relation with respect to thebottom 7 of the mold. As will be seen'from Figure 4, when the slabs ofmetal are so placed in the mold, their upper edges are below the upperrim of the mold so that the metal may be allowed to flow over the top ofthe slab.

The metal which is to be united to the stainless steel, is heated to amolten state and poured into the mold about theslab. The metal used ispreferably mild steel, lO-point carbon steel having been found to givevery advantageous results.

After the metal has cooled, the composite ingot 9 is removed from'themold and again heated toca welding temperature. The composite ingot 9 ishot passed one or more times through rolls to spread it out into thecomposite sheet illustrated at 10 in Figure 6.

After this, the marginal edges 11 are clipped o if along the line X-X ofFigure 6. The metal at this stage of the process is illustrated as themulti-ply sheet 12 of Figure 7 However, the plies 13 0f the sheet 12 maybe easily separated, in fact rolling strains may cause them to pop apartafter the margins have been sheared so as to form the individual sheet13 of Figure 8. The sheet 13 is composed of the upper prepared stainlesssteel surface 14 and the layer of backing metal 15. The separating,composition is almosty completely dissipated 'in the rolling processand may be Veasily'cleaned off the surface of the metal. However,frequently it is not even necessary to brush this composition from themetal.

By this process the ingot may be rolled to s1 1ch an extent that thelayer of surfacing metal is reduced to a thin coating similar tol thatobtained in electroplating processes. The composite metal has itslaminations firmly joined together, as complete welding takes placeduring the subsequent heating duce a largesmooth, cleaned surface from asmall smooth and cleaned surface by placing two slabs of the same, ordissimilar'metals with their prepared surfaces adjacent, separated onlyby the separating composition, welding the adjacent edges and thenheating androlling the multi-ply slab to produce the enlarged 'preparedsurface.

Further, if desired, as in rolling high speed steel, metal of the sameanalysis may be poured around the prepa-red slabs or the like and theingot so cast then rolled and separated in accordance with the processherein described.

Figure 9 illustrates a mold 17 having multiple pouring spaces 18 and 19partially separated by a diaphragm 20. The diaphragm may be two thinsheetslof metal coated 0n their adjacent surfaces with the separatingcomposition. It will be understood that a mold such as shown at 17 neednot be limited to twopouring spaces but may be provided with any numberof pouring spaces according to the capacity and requirements ofthepouring apparatus. Y

It will be seen that this invention provides a simple, expedient, andeconomical method of forming composite sheets of metal. It provides aneasy, economical method of coating steel with a layer of smooth,prepared stainless steel or other desired alloy or metal. It provides avery expedient method of producing a large, smooth metal surface withoutthe necessity of the costly grindingI and polishing operationsheretofore in use. I

While I have described my invention particularly with respect to thecoating of steel with stainless steel, it will be understood that myinvention is practicable for forming man other composite metal sheets.The pro uct of this invention can be used for forming any sort of sheetmetal ware where it is important to have one or more non-corrodiblesurface.

The process of this invention is very ecopomical since the large powerconsumption ordinarily required in rolling` thin sheets is to a largeextent eliminated, due to the fact that the final rolling in thisprocessis obviously only to a thickness of twice or more the thickness of thefinal sheet.

If the abutting surfaces of the slabs used are such as do notweldtogether, the separatthe ingot may be given any number of coldpasses after the first hot pass, and I do not wish to be limitedotherwise than is necesvsary by the prior art and the scope of theappended claims.

I claim as my invention:

1. The method of forming composite` metallic sheets each having a smoothsurface, which comprises preparing each of two metal slabs with apickled and smooth surface, coating the prepared surfaces with a sepa--rating and ynon-bonding compositionpress ing the slabs into contact withtheir prepared surfaces in juxtaposed relation and casting a metalentirely about said slabs.

2. The method of forming composite me.- tallic sheets each having asmooth surface,A which comprises preparing a surface on each of twometal slabs, coating the prepared surfaces with a separatingcomposition, pressing the slabs into contact with their preparedsurfaces in juxtaposed relation, sealing said common prepared surfacesaround the boundary thereof, casting a metal entirely about saidslabs,and rolling the ingot thus formed.

3. The method of forming composite Inetallic sheets having smoothsurfaces, which comprises preparing a pickledv and smooth surface oneach of two metal slabs, coating the prepared surfaces with anon-bonding composition, pressing the slabs into contact with theirprepared surfaces in juxtaposed relation, casting a metal entirely aboutsaid slabs, reheating the ingot thus formed to a forging temperature,rolling the ingot and cutting 0H the united marginal edges of the rolledarticle to form separate metallic .l f

sheets each with a smooth surface.

4. The method of forming polished com- -posite metallic sheets, whichcomprises polishing a surface of each of two stainless steel slabs,coating the polished surfaces with a separating composition, pressingthe slabs into contact with their polished surfaces in juxtaposedrelation, then sealing their marginal edges surrounding their commonsurfaces hermetically, and pouring a metal entirely about said slabs.

5. The method of forming composite metallic sheets, which comprisespickling and smoothing a surface of each of two stainless steel slabs,coating the prepared surfaces with a separating and non-bondingcomposition, pressing the slabs into contact with their preparedsurfaces in juxtaposed relation, pouring a metalentirely about said,slabs, reheating the ingot thus formed to a forging temperature,rollin-g the ingot and removing the united marginal edges of the rolledarticle to form separate composite metallic sheets, each having a smoothsurface.

6. The method of lforming composite metallic sheets,'which comprisespickling and smoothing a surface of 'each of two stainless steel slabs,coating the smoothed surfaces with a separating and non-bondingcomposition, pressing the slabs into contact with said surfaces injuxtaposed relation, and casting a mild steel entirely about said slabs.

7. The method of forming composite metallic sheets, which comprisespreparing a surface of each of two stainless steel slabs, coating theprepared surfacekwith a nonbonding composition, pressing the slabs intocontact with their prepared surfaces in juxtaposed relation, sealing thecommon prepared surfaces at the boundaries thereof,l casting a mildsteel entirely about said slabs, reheating the ingot thus formed toVforging temperature, rolling said ingot and cutting the united marginaledges ofthe rolled article to permit separation thereof into twocomposite metallic sheets.

8. The method of forming a composite metallic article, which comprisespreparing a surface of each of two metal slabs, coating the preparedsurfaces with a composition comprislng a composition containing redlead, pressing the slabs into Contact with their prepared surfaces injuxtaposed relation, casting a metal entirely about said slabs,

- reheating the ingot thus formed to a forging temperature, rolling thesame, and cutting off the united marginal edges of the rolled sheet toseparate-into two sheets. Y

9. The steps in the rocess of forming aV composite metallic artlcle,which comprise coating preparedsurfaces ofV metal slabs with acompositionV comprising water glass -their 'marginal ed es Wit and redlead, and unitin said slabs along vthe coated sur-x' faces in juxtaposealed relation for protection of said surfaces during'subsequent castinand rolling operations.

10. .themanufacture of a composite mei mui@ article -b wading and rouinghaving a polished sur ace thereon without polishing treatment subsequentto rolling the method which comprisespolishin a sur ace of a pairv 'ofmetal slabs, bringing t e polished surfaces into juxtaposed relationwith a film of a separating `and protecting composition therebetween,welding a backin `of another material about -saidf'jslabs by rol 'ng,and then 'separating the-polished surfaces.

11. In the manufacture of a composite metalic article by casting androlling having a polished surfac'e thereon without polishing treatmentsubsequent to rolling, the methodl which comprises polishing a surfaceof a pair of metal'slabs, bringing the polished surfaces into juxtaposedrelation with a- 111mtherebetween, castinga backing of another materialYabout said slabs, rolling the ingot thus formed, and then separatingthepolished surfaces.

l2. In the manufacture of a composite metallic article by welding androlling having a. polished surface thereony without polishing ytreatmentsubsequent to rolling,the method which comprises polishing a surface ofa plurality of metal slabs, assembling said slabs to form a core withthe polished surfaces in" juxtaposed relation and with a film of aseparating and protecting composition between the polished surfaces,sealing the edges of v said slabs to form vapor-tight envelopes for theseparating composition, casting another metal about said core, rollingthe ingot thus formed, and then separating the polished surfaces.

13. In the manufacture of a composite metal article by'casting a metalabout a core of Yjuxtaposed metal slabs, the steps comprising les ofsaid slabs to form an envelope for thecomposition, and then castingmetal about said slabs;

15. The method of forming a composite' article which comprisespositioning metal slabs in juxtaposed relation with a separatingcomposition therebetween, `welding the edges of said slabs to form anenvelope for the separating composition, casting metal about said slabsformed? l i 16. The method of forming a composite metal article, whichcomprises forming acore of slabs of a rustless ferrous composition Yinjuxtaposed relation with a separating composition therebetween,sealingthe edges of said slabs to form a vapor-tight envelope for saidseparating composition, and thencasting a metal about the core.

17. The method of `forming a composite metal article, which comprisesforming a core of 'juxtaposed stainless steel slabs with a separatingcomposition therebetween, sealing the edges of said slabs to form avapor-tight envelope `for said separating composition,

, and then rolling the ingotso j.

casting a metal about said core adapted to unite with said slabs, andthen rolling the in- A' tallic article, which comprises forming a core iof two juxtaposed slabs of a non-rusting alloy p l with a separatingcomposition therebetween, of ,a separating and pgotectingfcomplosition--fweldingthe edges of said slabs to form.r antenvelope for thecomposition, and casting metal 1,sos,749

about the core.

19. The method of forming a. composite metallic article, which comprisesformin a core of two juxtaposed rustless iron slabs with a separatingcomposition therebetween, weldinl'g''the edges of said slabs to formanenvelope for'said separating composition castin 'a'mild steel about saidslabs, and then ro ling the ingot thus formed to complete the weldbetween said mild steel and said slabs and to reduce the thickness ofthe composite article to sheet form. v

20. The methodof forming a composite metallic article, which comprisesforming a I core oftwo juxtaposed 'metal slabs with a separating mediumtherebetween, uniting said slabs about the edges of their commonsurfaces to form an envelope -for said separat.

ing medium, casting a metal about said slabs, rheatingthe-ingot thusformed to forging temperature, and then rolling the ingot,

2l. Thejmethodof forming a composite metallic article, which comprisesforming a core of two juxtaposed slabs of chromium steel alloy with aseparating composition therebetween, welding the edges surrounding theircommon surfaces to form an envelope for said composition, casting ametal about said slabs, reheating the ingot thus formed to' forgingtemperature, and then rolling the ingot.

- In testimony whereof I have hereunto subscribed my name at Chicago,`Cook County,

Illinois.

STEPHEN IN GERSOLL.

